The overall objective of the proposed research is to investigate cellular autoimmunity to the skin by in vitro methods, with the aim of determining the role of such immunity in human skin disease. Suspensions of epidermal cells, prepared from biopsies of normal and diseased human skin, would be used as stimulator and target cells in a variety of in vitro assays of cellular immunity, with lymphocytes obtained from human peripheral blood as responder and effector cells. The ability of patient epidermal cells to stimulate blastogenesis in their own lymphocytes and to cause the release of lymphokines would be determined in mixed leukocyte-epidermal cell cultures and in assays for macrophage migration inhibitory factor and lymphotoxin. The cytotoxicity of patient lymphocytes towards their own epidermal cells would be determined in chromium-release assays for both direct cell-mediated cytotoxicity and antibody-dependent cell mediated cytotoxicity. The first phase of the investigation would entail a survey of patients with a variety of dermatitides for evidence of cellular immunity to their own epidermal cells. In the second phase the reproducibility and specificity of significant positive reactions obtained in the first phase would be determined. The third phase would include clinical correlations of the in vitro assays, with an evaluation of their diagnostic potential and a more detailed basic study of the reactions using purified or fractionated effector cell populations.